EP0144853B1

EP0144853B1 - Semicarbazide derivatives, processes for preparation thereof and pharmaceutical composition comprising the same

Info

Publication number: EP0144853B1
Application number: EP84114005A
Authority: EP
Inventors: Osamu Nakaguchi; Norihiko Shimazaki; Yoshio Kawai; Masashi Hashimoto; Michie Nakatuka
Original assignee: Fujisawa Pharmaceutical Co Ltd
Current assignee: Fujisawa Pharmaceutical Co Ltd
Priority date: 1983-11-21
Filing date: 1984-11-20
Publication date: 1990-09-26
Also published as: DE3483308D1; US4725608A; EP0144853A3; EP0144853A2

Description

The present invention relates to novel semicarbazide derivatives. More particularly, it relates to novel semicarbazide derivatives which have antiinflammatory and analgesic activities, to processes for preparation thereof, to pharmaceutical composition comprising the same, and especially to pharmaceutical compositions for therapeutical use in the treatment of inflammation and various pains in human beings and animals.
Accordingly, one object of this invention is to provide novel semicarbazide derivatives which are useful as antiinflammatory and analgesic agents.
Another object of this invention is to provide processes for preparation of said semicarbazide derivatives.
A further object of this invention is to provide pharmaceutical composition comprising, as an active ingredient, said semicarbazide derivative.
Still further object of this invention is to provide pharmaceutical compositions comprising said semicarbazide derivatives useful in the treatment of inflammation and various pains in human beings and animals.
Some N-substituted-1,2,3,6-tetrahydropyridine derivatives having antiinflammatory and analgesic activities have been known as described, for example, in U.S. Patent 4,088,653 and Journal of Medicinal Chemistry Vol. 25, 720-723, 1982.
And some semicarbazide derivatives having similar chemical structure to the object compounds of this invention have been known as described, for example, in Journal of Medicinal Chemistry Vol. 11, 171-172, 1968, Journal of Chemical Society 1956, 2160-2165 and France Patent 1,521,959, Journal of Pharmaceutical Sciences Vol. 72, 1213-1215, 1983, G.B. Patents 2,058,762 and 1,382,974, U.S. Patent 4,013,699, German Patent 2,801,187 and Switzerland Patents 480,308 and 480,309. In these compounds, the compounds which possess antiinflammatory and analgesic activities have been known as described only in said Switzerland patent 480,308, but the substituent of these compounds is substituted phenylamino while the one of our compounds is tetrahydropyridyl.
The object semicarbazide derivatives are novel and can be represented by the following general formula [I]:
wherein

R' is hydrogen,
R² and R³ are taken together with the adjacent nitrogen atom to form tetrahydropyridyl optionally substituted with phenyl,
R⁴ is naphthyl or phenyl which may have substituent(s) selected from C₁ to C₆ alkyl, halogen, C₁ to C₆ alkylamino, halo(C, to C₆)alkyl, hydroxy, C₁ to C₆ alkanoyl, C₁ to C₆ alkoxycarbonyl, phenoxycarbonyl, benzyloxycarbonyl and carboxy,
R⁵ is hydrogen or C₁ to C₆ alkyl, and
X is 0 or S.

Preferable example of tetrahydropyridyl formed by R², R³ and the adjacent nitrogen atom may be 1,2,3,6-tetrahydropyridin-1-yl. This 1,2,3,6-tetrahydropyridin-1-yl may be substituted with phenyl.
Preferable example of X is 0.
Preferable example of R4 is phenyl. This phenyl may be substituted with substituent(s) selected from halogen and C, to C₆ alkylamino.
The object compound [I] and its pharmaceutically acceptable salt can be prepared by the following processes.

wherein

R¹, R², R³, R⁴, R⁵and X are each as defined above,
Y is hydrogen or phenyl,
Rf is naphthyl or phenyl substituted with C, to C₆ alkoxycarbonyl, phenoxycarbonyl or benzyloxycarbonyl, and
is naphthyl or phenyl substituted with carboxy.

In the above and subsequent description of the present specification, suitable examples of the various definitions to be included within the scope of the invention are explained in detail in the following.
The term "lower" is intended to mean a group having 1 to 6 carbon atom(s), unless otherwise provided.
Suitable examples of lower alkyl for R⁵ may be a straight or branched one such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl.
Suitable example of the heterocyclic group formed by R², R³ and the adjacent nitrogen atom may be 1,2,3,6-tetrahydropyridin-1-yl. These heterocyclic groups may be substituted with the phenyl group as exemplified before. Suitable examples of these heterocyclic groups having the phenyl group may be 4-phenyl-1,2,3,6-tetrahydropyridin-1-yl.
The phenyl or naphthyl group for R⁴ may be substituted with substituent(s) selected from the aforementioned lower alkyl; halogen [e.g. fluorine, chlorine, bromine and iodine]; lower alkylamino [e.g. methylamino, ethylamino, propylamino, hexylamino, dimethylamino, diethylamino, dipropylamino, dihexylamino]; halo(lower)alkyl [e.g. chloromethyl, fluoromethyl, bromomethyl, difluoromethyl, dichloromethyl, trifluoromethyl, trichloromethyl, 2-fluoroethyl]; hydroxy; lower alkanoyl [e.g. formyl, acetyl, propionyl, butyryl, isobutyryl, pivaloyl, valeryl, hexanoyl]; lower alkoxycarbonyl [e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, hexyloxycarbonyl], phenoxycarbonyl, benzyloxycarbonyl, and carboxy.
Suitable examples of the phenyl or naphthyl group for R⁴ having such substituent(s) may be lower alkyl substituted phenyl or naphthyl [e.g. o-tolyl, m-tolyl, p-tolyl], halogenated phenyl or naphthyl [e.g. 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-iodophenyl, 2,4-difluorophenyl, 3,4-difluorophenyl, 4-fluoronaphthalen-1-yl], lower alkylamino substituted phenyl or naphthyl [e.g. 4-methylaminophenyl, 4-dimethylaminophenyl, 4-diethylaminophenyl, 5-dimethylaminonaphthalen-1-yl], halo(lower)alkyl substituted phenyl or naphthyl [e.g. 4-trifluoromethylphenyl, 2-trifluoromethylphenyl, 4-trichloromethylphenyl, 4-trifluoromethyl- naphthalen-1-yl], hydroxy substituted phenyl or naphthyl [e.g. 4-hydroxyphenyl, 3-hydroxyphenyl, 2-hydroxyphenyl, 2-hydroxynaphthalen-1-yl], lower alkanoyl substituted phenyl or naphthyl [e.g. 4- formylphenyl, 4-acetylphenyl, 2-propionylphenyl], C, to C₆ alkoxycarbonyl substituted phenyl or naphthyl [e.g. 4-methoxycarbonylphenyl, 2-ethoxycarbonylphenyl, 4-phenoxycarbonylphenyl, 4-benzyloxy- carbonylphenyl], carboxy substituted phenyl or naphthyl [e.g. 4-carboxyphenyl, 3-carboxyphenyl, 2-carboxyphenyl], lower alkyl and halogen substituted phenyl or naphthyl [e.g. 4-fluoro-2-methylphenyl, 2-fluoro-4-methylphenyl, 4-fluoro-2-ethylphenyl, 2,4-difluoro-6-methylphenyl].
Suitable examples of phenyl or naphthyl substituted with C₁ to C₆ alkoxycarbonyl, phenoxycarbonyl or benzyloxycarbonyl for
and the carboxy substituted phenyl or naphthyl for
can be referred to those exemplified for R⁴ as mentioned above.
Suitable pharmaceutically acceptable salts of the object compounds [I] are conventional non-toxic salts and include a metal salt such as an alkali metal salt [e.g. sodium salt, potassium salt] and an alkaline earth metal salt [e.g. calcium salt, magnesium salt], an ammonium salt, an organic base salt [e.g. trimethylamine salt, triethylamine salt, pyridine salt, picoline salt, dicyclohexylamine salt, N,N'-dibenzylethylenediamine salt], an organic acid salt [e.g. formate, acetate, maleate, tartrate, methanesulfonate, benzenesulfonate, toluenesulfonate], an inorganic acid salt [e.g. hydrochloride, hydrobromide, sulfate, phosphate], and a salt with an amino acid [e.g. arginine salt, aspartic acid salt, glutamic acid salt].
In this respect, it is to be noted the compounds [la], [Ib], [le] and [If] are included within the scope of the compound [I], and accordingly the suitable salts of these compounds [la], [lb], [le] and [If] are to be referred to those as exemplified for the object compound [I] mentioned above.
The processes for preparing the object compounds [I] and their salts are explained in detail in the following.

Process 1

The object compound [la] and its salt can be prepared by reacting a compound [II] or its salt with a compound [III] or its salt.
Suitable salts of the compounds [II] and [III] may be the same as those exemplified for the compound [I].
This reaction is usually carried out in a solvent such as water, methanol, ethanol, dioxane, tetrahydrofuran, benzene, chloroform, methylene chloride or any other organic solvent which does not adversely influence the reaction.
The reaction temperature is not critical, and the reaction is usually carried out under cooling to warming.

Process 2

The object compound [I] and its salt can be prepared by reacting a compound [II] or its salt with a compound [IV] or its reactive derivative at the carboxy, dithiocarboxy, mercaptocarbonyl or hydroxy thiocarbonyl group or a salt thereof.
Suitable salts of the compound [II] may be an acid addition salt exemplified for the compound [I].
Suitable reactive derivative at the carboxy, dithiocarboxy, mercaptocarbonyl or hydroxy thiocarbonyl group of the compound [IV] may include an ester, an acid halide and an acid anhydride. The suitable examples of the reactive derivatives may be an acid halide [e.g. acid chloride, acid bromide]; a symmetrical acid anhydride; a mixed acid anhydride with an acid such as aliphatic carboxylic acid [e.g. acetic acid, pivalic acid], substituted phosphoric acid [e.g. dialkylphosphoric acid, diphenylphosphoric acid]; an ester such as lower alkyl ester [e.g. methyl ester, ethyl ester, propyl ester, hexyl ester], substituted or unsubstituted ar(lower)alkyl ester [e.g. benzyl ester, benzhydryl ester, p-chlorobenzyl ester], substituted or unsubstituted aryl ester [e.g. phenyl ester, tolyl ester, 4-nitrophenyl ester, 2,4-dinitrophenyl ester, pentachlorophenyl ester, naphthyl ester], or an ester with N,N-dimethylhydroxylamine, N-hydroxysuccinimide, N-hydroxyphthalimide or 1-hydroxy-6-chioro-1H-benzotriazo!e. These reactive derivatives can be optionally selected according to the kind of the compound [IV] to be used.
Suitable salts of the compound [IV] and its reactive derivative may be the same as those exemplified for the compound [I].
The reaction is usually carried out in a conventional solvent such as water, acetone, dioxane, chloroform, methylene chloride, ethylene chloride, tetrahydrofuran, ethyl acetate, N,N-dimethylformamide, pyridine or any other organic solvent which does not adversely influence the reaction. Among these solvents, hydrophilic solvents may be used in a mixture with water.
When the compound [IV] is used in a free acid form or its salt form in the reaction, the reaction is preferably carried out in the presence of a conventional condensing agent such as N,N'-dicyclohexylcarbodiimide, N-cyclohexyl-N'-morpholinoethylcarbodiimide, N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide, thionyl chloride, oxalyl chloride, lower alkoxycarbonyl halide [e.g. ethyl chloroformate, isobutyl chloroformate], 1-(p-chlorobenzenesulfonyloxy)-6-chloro-1H-benzotriazole. The reaction is also preferably carried out in the presence of a conventional base such as triethylamine, pyridine, sodium hydroxide.
The reaction temperature is not critical, and the reaction can be carried out under cooling to heating.

Process 3

The object compound [I] and its salt can be prepared by reacting a compound [V] or its reactive derivative at the carboxy, dithiocarboxy, mercaptocarbonyl or hydroxy thiocarbonyl group or a salt thereof with a compound [VI] or its salt.
Suitable reactive derivatives at the carboxy, dithiocarboxy, mercaptocarbonyl or hydroxy thiocarbonyl group of the compound [V] and suitable salts of the compound [V] and its reactive derivative may be the same as those exemplified for the compound [IV] in the above Process 2.
Suitable salts of the compound [VI] may be the same as those exemplified for the compound [I].
This reaction can be carried out substantially in the same manner as Process 2, and therefore the reaction made and reaction conditions [e.g. solvent, condensing agent, reaction temperature] of this reaction are to be referred to those as explained in Process 2.

Process 4

The object compound [Ib] and its salt can be prepared by reducing a compound [VII] or its salt.
The reaction can be carried out in a conventional manner, namely, chemical reduction or catalytic reduction.
Suitable reducing agents to be used in chemical reduction are a metal hydride compound such as aluminum hydride compound [e.g. lithium aluminum hydride, sodium aluminum hydride, aluminum hydride, lithium trimethoxyaluminum hydride, lithium tri-t-butoxyaluminum hydride], borohydride compound [e.g. sodium borohydride, lithium borohydride, sodium cyanoborohydride, tetramethylammonium borohydride, borane, diborane].
Suitable catalysts to be used in catalytic reduction are conventional ones such as platinum catalyst [e.g. platinum plate, spongy platinum, platinum black, colloidal platinum, platinum oxide, platinum wire], palladium catalyst [e.g. spongy palladium, palladium black, palladium oxide, palladium on carbon, colloidal palladium, palladium on barium sulfate, palladium on barium carbonate], nickel catalyst [e.g. reduced nickel, nickel oxide, Raney nickel], cobalt catalyst [e.g. reduced cobalt, Raney cobalt], iron catalyst [e.g. reduced iron, Raney iron], copper catalyst [e.g. reduced copper, Raney copper, Ullman copper].
The reaction of this process is usually carried out in a solvent such as water, alcohol [e.g. methanol, ethanol, propanol], acetic acid, diethyl ether, dioxane, tetrahydrofuran, or a mixture thereof.
The reaction is preferably carried out under somewhat milder conditions such as under cooling to warming.
In this process, the pyridinio moiety of the compound [VII] is reduced to piperidino, 1,4-dihydropyridin-1-yl, 1,2-dihydropyridin-1-yl or 1,2,3,6-tetrahydropyridin-1-yl group according to the reducing method and the reagent to be used in this process.

Process 5

The object compound [If] and its salt can be prepared by subjecting a compound [le] or its salt to de-esterification reaction.
The reaction is carried out in accordance with a conventional method such as hydrolysis, reduction.
The hydrolysis is preferably carried out in the presence of a base or an acid including Lewis acid. Suitable base may include an inorganic base and an organic base such as an alkali metal [e.g. sodium, potassium], an alkaline earth metal [e.g. magnesium, calcium], the hydroxide or carbonate or bicarbonate thereof, trialkylamine [e.g. trimethylamine, triethylamine], picoline, 1,5-diazabicyclo[4,3,0]non-5-ene, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undec-7-ene. Suitable acid may include an organic acid [e.g. formic acid, acetic acid, propionic acid, trichloroacetic acid, trifluoroacetic acid] and an inorganic acid [e.g. hydrochloric acid, hydrobromic acid, sulfuric acid]. The elimination using Lewis acid such as trihaloacetic acid [e.g. trichloroacetic acid, trifluoroacetic acid] is preferably carried out in the presence of cation trapping agents [e.g. anisole, phenol].
The reaction is usually carried out in a solvent such as water, an alcohol [e.g. methanol, ethanol], methylene chloride, tetrahydrofuran, a mixture thereof or any other solvent which does not adversely influence the reaction. A liquid base or acid can be also used as the solvent. The reaction temperature is not critical and the reaction is usually carried out under cooling to warming.
The reduction can be applied preferably for elimination of the ester moiety such as 4-nitrobenzyl, 2-iodoethyl, 2,2,2-trichloroethyl. The reduction method applicable for the elimination reaction may include chemical reduction and catalytic reduction.
Suitable reducing agents to be used in chemical reduction are a combination of metal [e.g. tin, zinc, iron] or metallic compound [e.g. chromium chloride, chromium acetate] and an organic or inorganic acid [e.g. formic acid, acetic acid, propionic acid, trifluoroacetic acid, p-toluenesulfonic acid, hydrochloric acid, hydrobromic acid].
Suitable catalysts to be used in catalytic reduction may be the same catalysts as exemplified in Process 4.
The reduction is usually carried out in a conventional solvent which does not adversely influence the reaction such as water, methanol, ethanol, propanol, N,N-dimethylformamide, or a mixture thereof. Additionally, in case that the above-mentioned acids to be used in chemical reduction are in liquid, they can also be used as a solvent. Further, a suitable solvent to be used in catalytic reduction may be the above-mentioned solvent, and other conventional solvent such as diethyl ether, dioxane, tetrahydrofuran, or a mixture thereof.
The reaction temperature of this reduction is not critical and the reaction is usually carried out under cooling to warming.
The object compounds [I] obtained by the above processes are isolated and purified by a conventional manner such as recrystallization, reprecipitation, column chromatography.
Among the starting compounds [IV], [V] and [VII], new compounds can be prepared by the methods of Preparations mentioned later and any process known in the art for preparing structurally analogous compounds thereto.
It is to be noted that each of the object compound [I] and the starting compounds [II] to [VII] may include one or more stereoisomers due to asymmetric carbon atoms in the molecule, and all of such isomers of the compounds [I] to [VII] are included within the scope of this invention.
The new semicarbazide derivatives [I] and pharmaceutically acceptable salt thereof possess antiinflammatory and analgesic activities, and are useful for a therapeutic treatment of inflammation and various pains [e.g. headache, toothache, menorrhalgia].
For therapeutic purpose, the compounds according to the present invention can be used in a form of pharmaceutical preparation containing one of said compounds, as an active ingredient, in admixture with a pharmaceutically acceptable carrier such as an organic or inorganic solid or liquid excipient suitable for oral or parenteral administration. The pharmaceutical preparations may be capsules, tablets, dragees, granules, solution, suspension, emulsion. If desired, there may be included in these preparations, auxiliary substances, stabilizing agents, wetting or emulsifying agents, buffers and other commonly used additives.
While the dosage of the compounds [I] will vary depending upon the age and condition of the patient, an average single dose of about 0.1 mg, 1 mg, 10 mg, 50 mg, 100 mg, 250 mg, 500 mg and 1000 mg of the compounds [I] may be effective for treating inflammation and various pains. In general, amounts between 0.1 mg/body and about 1,000 mg/body may be administered per day.
In order to illustrate the usefulness of the object compounds [I], the pharmacological test data of the representative compound [I] are shown in the following.

[A] ANTIINFLAMMATORY ACTIVITY
(1) Carrageenin foot edema
(i) Test Method

Five male Sprague-Dawley rats weighing about 200 g were used per group.
Paw edema was induced by subplantar injection of 1 % carrageenin (0.1 ml/rat) into the right hind paw. The test drug was suspended in 0.5% methylcellulose and administered orally 60 minutes before phlogogen. Paw volume was measured with plethysmometer (Ugo Bazil Co., Ltd.) by water displacement immersing the paw to the lateral malleolus. The difference of paw volume before and 3 hours after the phlogogen was designated as edema volume. The data were analyzed statistically by student's t-test.

(ii) Test Results
(2) Arthus foot edema
(i) Test Method

Five male Sprague-Dawley rats weighing about 200 g were used per group.
Paw edema was induced by intravenous injection of egg albumin (0.5 mg/rat) and subplantar injection of anti egg albumin antiserum (0.1 ml/rat) in Arthus type foot edema. The test drug was suspended in methylcellulose and administered orally 60 min. before phlogogen. Paw volume was measured with plethysmometer (Ugo Bazil Co., Ltd.) by water displacement immersing the paw to the lateral malleolus. The difference of paw volume before and 3 hours after the phlogogen was designated as edema volume. The data were analyzed statistically by student's t-test.

(ii) Test Result
[B] ANALGESIC ACTIVITY
(1) Acetic acid induced writhing
(i) Test Method

Ten male ddY strain mice were used per group. To estimate the frequency of writhing syndrome, the animals were observed from 3 to 13 minutes after an intraperitoneal injection of 0.2 ml/10 g of 0.6% acetic acid. The drugs were given orally 60 minutes before acetic acid. The frequency of writhing syndrome in the treated animals were compared with that in the non-treated control animals.

(ii) Test Results

As being apparent from the above test results, the object compound [I] of the present invention are useful as antiinflammatory and analgesic agents.
The following Preparations and Examples are given for the purpose of illustrating the present invention in more detail.

Preparation 1

To a solution of N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and triethylamine (2.024 g) in methylene chloride (60 ml) was added a solution of phenyl chloroformate (1.566 g) in methylene chloride (40 ml) and the mixture was stirred for 4 hours at 5°C. Evaporation of the solvent gave a residue, which was extracted with ethyl acetate (150 ml). The extract was washed with water and dried over magnesium sulfate. The solvent was evaporated in vacuo to give N-(phenoxycarbonylamino)-1,2,3,6-tetrahydropyridine (2.01 g), which was recrystallized from diisopropyl ether to give the desired compound (0.732 g) as colorless needles.

mp: 124―125.5°C.
IR (Nujol): 3230, 1720, 1600, 1540 cm^-1.

NMR (CDCI₃, δ): 2.30 (2H, m), 3.06 (2H, t, J=6Hz), 3.47 (2H, m), 5.69 (2H, m), 6.33 (1 H, s), 7.10-7.47 (5H, m).

Analysis: Calcd. for C₁₂H₁₄N₂O₂
Calcd.: C 66.04, H 6.47, N 12.84
Found: C 66.28, H 6.44, N 13.08

Preparation 2

N-(Phenoxycarbonyl)-2-fluoroaniline (3.76 g) was obtained according to a similar manner to that of Preparation 1 from 2-fluoroaniline (2.22 g) and phenyl chloroformate (3.13 g).

IR (Nujol): 3310, 1720, 1530 cm-¹.
NMR (CDCI₃, δ): 6.9-7.60 (9H, m), 8.20 (1H, br.s).

Preparation 3

4-(Phenoxycarbonylamino)-N,N-dimethylaniline (9.06 g) was obtained according to a similar manner to that of Preparation 1 from 4-amino-N,N-dimethylaniline (5.45 g) and phenyl chloroformate (7.52 g).

mp: 163.5-164.5°C.
IR (Nujol): 3340, 2940, 2855, 1720 cm^-1.

Preparation 4

A mixture of N-aminopyridinium iodide (0.67 g), phenylisocyanate (0.39 g) and triethylamine (0.34 g) in dioxane (12 ml) was stirred for 3 hours under ice-bath cooling. The reaction mixture was diluted with water (12 ml), concentrated to a volume of ca. 5 ml, and then diluted with water. The precipitates were filtered off and the filtrate was evaporated to dryness to give N-(phenylcarbamoylimino)pyridinium ylide, which was used without further purification for the next reaction.

Preparation 5

To a stirred solution of N-aminopyridinium iodide (4.44 g) and triethylamine (2.02 g) in dry dioxane (60 ml) was added a solution of 4-fluorophenyl isocyanate (3.02 g) in dry dioxane (20 ml) under ice-bath cooling. After stirring for one hour, the reaction mixture was evaporated to dryness. The residue was washed with water and dried to give N-[[(4-fluorophenyl)carbamoyl]imino]pyridinium ylide (4.24 g).

mp: 207-209°C.
IR (Nujol): 3250, 3200, 3100, 1630, 1620 cm^-1.
NMR (DMSO-d_s, δ): 6.78-7.93 (7H, m), 8.28 (1H, s), 8.88-9.05 (2H, m).

Preparation 6

A mixture of N-aminopyridinium iodide (1.11 g), triethylamine (0.50 g) and 4-fluoro-N-phenoxycarbonylaniline (1.15 g) in tetrachloroethylene (40 ml) was stirred under reflux for 5 hours. After evaporation of the solvent, the residue was washed with diisopropyl ether, triturated with diethyl ether, washed with water and dried to give N-[[(4-fluorophenyl)carbamoyl]imino]pyridinium ylide (0.54 g).

IR (Nujol): 3250, 3200, 3100, 1630, 1620, 1590 cm^-1.

Preparafion 7

N-[[(4-Fluorophenyl)carbamoyl]imino]pyridinium ylide (0.93 g) was obtained according to a similar manner to that of Preparation 6 from phenoxycarbonyliminopyridinium ylide (2.14 g) and 4-fluoroaniline (1.11 g).

IR (Nujol): 3250, 3200, 3100, 1630, 1620 cm-¹.
NMR (DMSO-d_s, δ): 6.78-7.93 (7H, m), 8.28 (1 H, s), 8.88-9.05 (2H, m).

Example 1

N-Amino-1,2,3,6-tetrahydropyridine hydrochloride (3.42 g) was dissolved in a mixture of dioxane (30 ml) and water (20 ml). The solution was adjusted to pH 7.5 with 1N-aqueous sodium hydroxide and to the resultant mixture was added a solution of 4-fluorophenylisocyanate (0.548 g) in dioxane (5 ml). Then, the mixture was kept to pH 7.5 and stirred for 2 hours at 5°C. After evaporation of organic solvent, the crystalline product was collected by filtration and recrystallized from diisopropyl ether to give white needles of N-[[(4-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (0.73 g).

mp: 156-157°C.
Mass: m/e = 235 (M⁺).
IR (Nujol): 3380, 3190, 3100, 1680, 1660 cm^-1.
NMR (CDCI₃, δ): 2.31 (2H, m), 2.92 (2H, t, J=_7Hz), 5.78 (2H, m), 6.87-7.48 (4H, m).
Analysis: Calcd. for C₁₂H₁₄FN₃O Calcd.: C 61.26, H 6.00, N 17.84
Found: C 61.37, H 6.06, N 18.04

Example 2

N-[[(4-Fluorophenyl)carbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine (1.07 g) was obtained according to a similar manner to that of Example 1 from N-amino-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (1.16 g) and 4-fluorophenylisocyanate (0.91 g).

mp: 200.5-212°C.
Mass: m/e = 311 (M⁺).
IR (Nujol): 3340, 3160, 3070, 1670, 1540 cm^-1.
NMR (DMSO-d_s, δ): 2.5-3.2 (4H, m), 3.3-3.7 (2H, m), 6.0-6.3 (1H, m), 6.9-7.8 (10H, m), 8.63 (1H, s).
Analysis: Calcd. for C₁₈H₁₈FN₃O
Calcd.: C 69.44, H 5.83, N 13.50
Found: C 69.43, H 5.90, N 13.49

Example 3

To a solution of N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and triethylamine (1.012 g) in dry methylene chloride (40 ml) was added a solution of 3-fluorophenyl isocyanate (1.37 g) in dry methylene chloride under ice-bath cooling. After stirring for one hour, the reaction mixture was evaporated to dryness. The residue was extracted with ethyl acetate (100 ml). The extract was washed with water, evaporated to dryness and recrystallized from ethyl acetate to give N-[[(3-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.43 g).

mp: 136.5-138.5°C.
IR (Nujol): 3280, 3200, 3100, 1685 cm-'.
NMR (CDCl₃, δ): 2.33 (2H, m), 2.98 (2H, m), 3.37 (2H, m), 5.71 (2H, m), 6.37 (1H, s), 6.57-7.60 (4H, m), 8.28 (1 H, s).
Analysis: Calcd. for C₁₂H₁₄FN₃O
Calcd.: C 61.26, H 6.00, N 17.86
Found: C 61.44, H 5.83, N 17.91

Example 4

N-[[(4-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.32 g) was obtained according to a similar manner to that of Example 3 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and 4-chlorophenyl isocyanate (1.536 g).

mp: 165.5-167.5°C.
IR (Nujol): 3330, 3170, 3100, 1685 cm^-1.
NMR (CDCI₃, δ): 2.35 (2H, m), 2.98 (2H, m), 3.37 (2H, m), 5.73 (2H, m), 6.25 (1H, s), 7.22 (2H, d, J=8Hz), 7.48 (2H, d, J=8Hz), 8.23 (1 H, s).
Analysis: Calcd. for C₁₂H₁₄ClN₃O
Calcd.: C 57.26, H 5.61, N 16.69
Found: C 57.15, H 5.87, N 16.78

Example 5

N-[[(3-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.52 g) was obtained according to a similar manner to that of Example 3 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and 3-chlorophenyl isocyanate (1.536 g).

mp: 145.5-147°C.
IR (Nujol): 3340, 3190, 3090, 1680 cm^-1.
NMR (CDCI₃, δ): 2.38 (2H, m), 3.02 (2H, m), 3.40 (2H, m), 5.73 (2H, m), 6.48 (1H, s), 6.93-7.30 (4H, m), 8.45 (1H, s).
Analysis: Calcd. for C₁₂H₁₄ClN₃O
Calcd.: C 57.26, H 5.61, N 16.69
Found: C 57.39, H 5.75, N 16.67

Example 6

N-[(p-Tolylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine (1.73 g) was obtained according to a similar manner to that of Example 3 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and 4-methylphenyl isocyanate (1.323 g).

mp: 179-180°C.
IR (Nujol): 3350, 3170, 3050, 1675 cm^-1.
NMR (CDCI₃, δ): 2.28 (3H, s), 2.28 (2H, m), 2.63 (2H, t, J=7Hz), 3.35 (2H, m), 5.70 (2H, m), 5.95 (1H, s), 7.07 (2H, d, J=8Hz), 7.37 (2H, d, J=8Hz), 8.08 (1H, s).
Analysis: Calcd. for C₁₃H₁₇N₃O
Calcd.: C 67.51, H 7.41, N 18.17
Found: C 67.85, H 7.58, N 18.12

Example 7

N-[[(4-Trifluoromethylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.9 g) was obtained according to a similar mannerto that of Example 3 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and 4-trifluoromethylphenyl isocyanate (1.871 g).

mp: 159.5―161°C.
IR (Nujol): 3340, 3200, 3100, 1690 cm-'.

NMR (CDCI₃, δ): 2.33 (2H, m), 2.97 (2H, t, J=_7Hz), 3.37 (2H, m), 5.70 (2H, m), 6.25 (1 H, s), 7.40-7.72 (4H, m), 8.20 (1 H, s).

Analysis: Calcd. for C₁₃H₁₄F₃N₃O
Calcd.: C 54.74, H 4.95, N 14.73
Found: C 55.18, H 5.05, N 14.79

Example 8

N-[(1-Naphthylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine (1.63 g) was obtained according to a similar manner to that of Example 3 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and 1-naphthyl isocyanate (1.692 g).

mp: 181.5-183.5°C.
IR (Nujol): 3350, 3175, 3075, 1675 cm^-1.

NMR (CDCI₃, δ): 2.40 (2H, m), 3.08 (2H, m), 3.48 (2H, m), 5.93 (2H, m), 6.28 (1H, s), 7.33-8.20 (7H, m), 8.87 (1 H, s).

Analysis: Calcd. for C₁₆H₁₇N₃O
Calcd.: C 71.89, H 6.41, N 15.72
Found: C71.98, H 6.47, N 15.65

Example 9

To a stirred solution of N-amino-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (1.05 g) in a mixture of dioxane (10 ml) and water (5 ml) was added 1 N sodium hydroxide solution (5 ml) under ice-bath cooling, and then a solution of 4-fluorophenyl isothiocyanate (1.15 g) in dioxane (5 ml) was added thereto. The mixture was stirred for 5 hours under ice-bath cooling. The reaction mixture was evaporated in vacuo and the residue was extracted several times with ethyl acetate. The combined extract was washed with water, dried over magnesium sulfate and evaporated in vacuo to give a crude product, which was recrystallized from ethyl acetate to give N-[[(4-fluorophenyl)thiocarbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine (1.05 g).

mp: 192.5-194.5°C.
IR (Nujol): 3300, 3125, 1540, 1510 cm^-1.

NMR (CDC1₃, δ): 2.72 (2H, m), 3.17 (2H, m), 3.58 (2H, m), 5.97 (2H, m), 6.83-7.63 (4H, m), 7.27 (5H, s), 7.83 (1 H, s), 9.12 (1H, s).

Analysis: Calcd. for C₁₈H₁₈FN₃S
Calcd.: C 66.03, H 5.54, N 12.83
Found: C 66.79, H 5.63, N 12.65

Example 10

N-Amino-1,2,3,6-tetrahydropyridine hydrochloride (3.768 g) was dissolved in a mixture of dioxane (60 ml) and water (30 ml). The solution was adjusted to pH 7 with 1 N-aqueous sodium hydroxide, and to the resultant mixture was added a solution of 4-fluorophenyl isothiocyanate (3.984 g) in dioxane (20 ml). The mixture was kept to pH 7.5 and stirred for 6 hours at ambient temperature. After evaporation of organic solvent, the residue was extracted with ethyl acetate (300 ml). The extract was washed with water and dried over magnesium sulfate. The solvent was distilled off to give a residue (1.5 g), which was subjected to column chromatography on silica gel (37 g) eluting with chloroform. The fractions containing the desired compound were combined and concentrated under reduced pressure. The residue was recrystallized from ethyl acetate to give white needles of n-[[(4-fluorophenyl)thiocarbamoyl]amino]-1,2,3,6-tetrahydropyridine (0.779 g).

mp: 163-164.5°C.
Mass: m/e = 251 (M^*).
IR (Nujol): 3260, 2930, 1540, 1505, 1460 cm^-1.
NMR (DMSO-d₆, δ): 2.88 (2H, m), 5.72 (2H, m), 7.00-7.73 (4H, m), 9.26 (1H, s), 9.60 (1H, s).
Analysis: Calcd. for C₁₂H₁₄N₃FS
Calcd.: C 57.35, H 5.61, N 16.72
Found: C 57.17, H 5.92, N 16.53

Example 11

The following compounds are obtained according to a similar manner to that of Example 1.

(1) N-[[(2-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 119―121°C. IR (Nujol): 3360, 3200, 3100, 1690, 1620, 1600 cm^-1.
(2) N-(Phenylcarbamoylamino)-1,2,3,6-tetrahydropyridine
- mp: 157-159°C.
- IR (Nujol): 3340, 3190, 3100, 1680 cm^-1.
(3) N-[[(4-Dimethylaminophenyl)carbamoyl]amino-1,2,3,6-tetrahydropyridine
- mp: 179.5-180°C.
- IR (Nujol): 1680 cm^-1.
(4) N-[[(4-Acetylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 142.5-143°C.
- IR (Nujol): 1685, 1670 cm^-1.
(5) N-[[(2,4-Difluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 136.5-137°C.
- IR (Nujol): 1695 cm-'.
(6) N-[[(4-Methoxycarbonylphenyl)carbamoyl]amino]-1 ,2,3,6-tetrahydropyridine
- mp: 182.5-184°C.
- IR (Nujol): 1715, 1680 cm-'.

Example 12

A solution of 4-fluoro-N-phenoxycarbonylaniline (2.29 g), N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.346 g) and triethylamine (1.02 g) in chloroform (25 ml) was refluxed for 20 hours. After evaporation of chloroform, the residue was extracted with ethyl acetate (100 ml). The extract was washed with water, dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel (20 g) using chloroform as an eluent to give N-[[(4-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.05 g).

mp: 156-157°C.
Mass: m/e = 235 (M⁺).
IR (Nujol): 3380, 3190, 3100, 1680, 1660 cm^-1.
NMR (CDCI₃, δ): 2.31 (2H, m), 2.92 (2H, t, J=7Hz), 5.78 (2H, m), 6.87-7.48 (4H, m).
Analysis: Calcd. for C₁₂H₁₄FN₃O
Calcd.: C 61.26, H 6.00, N 17.84
Found: C 61.37, H 6.06, N 18.04

Example 13

N-[[(2-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (0.56 g) was obtained according to a similar manner to that of Example 12 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (2.34 g) and 2-fluoro-N-phenoxycarbonylaniline (2.77 g).

mp: 119―121°C.
IR (Nujol): 3360, 3200, 3100, 1690, 1620, 1600 cm^-1.

NMR (CDCI₃, δ): 2.32 (2H, m), 2.98 (2H, m), 3.38 (2H, m), 5.71 (2H, m), 6.10 (1H, s), 6.94-7.20 (3H, m), 8.20-8.37 (1H, m), 8.53 (1H, s).

Analysis: Calcd. for C₁₂H₁₄FN₃O
Calcd.: C 16.26, H 6.00, N 17.86
Found: C 61.87, H 6.09, N 17.95

Example 14

N-[[(4-Dimethylaminophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.98 g) was obtained according to a similar manner to that of Example 12 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (2.02 g) and 4-(phenoxycarbonylamino)-N,N-dimethylaniline (2.56 g).

mp: 179.5-180°C.
IR (Nujol): 1680 cm^-1.
NMR (CDCI₃, δ): 2.26 (2H, m), 2.84 (6H, s), 2.70-3.13 (2H, m), 3.30 (2H, m), 5.66 (2H, m), 6.06 (1H, s).

Example 15

N-[[(4-Acetylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.72 g) was obtained according to a similar manner to that of Example 12 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (1.94 g) and 4'-(phenoxycarbonylamino)acetophenone (3.06 g).

mp: 142.5-143°C.
IR (Nujol): 1685, 1670 cm^-1.

Example 16

N-[[(2,4-Difluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.14 g) was obtained according to a similar manner to that of Example 12 from N-amino-1,2,3,6-tetrahydropyridine hydrochloride (2.22 g) and 2,4-difluoro-N-phenoxycarbonylaniline (2.74 g).

mp: 136.5-137°C.
IR (Nujol): 1695 cm-'.

NMR (CDCI₃, δ): 2.06-2.50 (2H, m), 2.73-3.09 (2H, m), 3.15-3.64 (2H, m), 5.56-5.87 (2H, m), 5.90-6.23 (1H, m), 6.59-7.13 (2H, m), 7.88-8.48 (2H, m).

Example 17

The following compounds are obtained according to a similar manner to that of Example 12.

(1) N-[[(4-Fluorophenyl)carbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine
- mp: 200.5-212°C.
- IR (Nujol): 3340, 3160, 3070, 1670, 1540 cm^-1.
(2) N-[[(3-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 136.5-138.5°C.
- IR (Nujol): 3280, 3200, 3100, 1685 cm^-1.
(3) N-[[(4-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 165.5-167.5°C.
- IR (Nujol): 3330, 3170, 3100, 1685 cm^-1.
(4) N-[[(3-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 145.5-147.0°C.
- IR (Nujol): 3340, 3190, 3090, 1680 cm^-1.
(5) N-[(p-Tolylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 179-180°C.
- IR (Nujol): 3350, 3170, 3050, 1675 cm^-1.
(6) N-[[(4-Trifluoromethylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 159.5―161°C.
- IR (Nujol): 3340, 3200, 3100, 1690 cm^-1.
(7) N-[(1-Naphthylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 181.5-183.5°C.
- IR (Nujol): 3350, 3175, 3075, 1675 cm^-1.
(8) N-(Phenylcarbamoylamino)-1,2,3,6-tetrahydropyridine
- mp: 157-159°C.
- IR (Nujol): 3340, 3190, 3100, 1680 cm-'.
(9) N-[(N-Methyl-N-phenylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 99-99.5°C.
- IR (Nujol): 3250, 2950, 2870, 1645 cm^-1.
(10) N-[[(4-Hydroxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 185.5-187°C.
- IR (Nujol): 3190, 1660 cm-'.
(11) N-[[(4-Methoxycarbonylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 182.5-183°C.
- IR (Nujol): 1715, 1680 cm-'.
(12) N-[[(4-Carboxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: >240°C.
- IR (Nujol): 1700 cm^-1.
(13) N-[[(4-Fluorophenyl)thiocarbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 163-164.5°C.
- IR (Nujol): 3260, 2930, 1540, 1505, 1460 cm^-1.
(14) N-[[(4-Fluorophenyl)thiocarbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine
- mp: 192.5―194.5°C.
- IR (Nujol): 3300, 3125, 1540, 1510 cm^-1.

Example 18

N-[[(4-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (0.70 g) was obtained according to a similar manner to that of Example 12 from N-(phenoxycarbonylamino)-1,2,3,6-tetrahydropyridine (1.09 g) and 4-fluoroaniline (0.555 g).

Example 19

N-[(N-Methyl-N-phenylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine (1.24 g) was obtained according to a similar manner to that of Example 12 from N-phenoxycarbonylamino-1,2,3,6-tetrahydropyridine (2.18 g) and N-methylaniline (2.19 g).

mp: 99-99.5°C.
IR (Nujol): 3250, 2950, 2870, 1645 cm-'.

NMR (CDCI₃, δ): 2.13 (2H, m), 2.86 (2H, t, J=6Hz), 3.16 (3H, s), 3.13-3.46 (2H, m), 5.23-5.76 (2H, m), 7.02-7.53 (5H, m).

Example 20

N-[[(4-Hydroxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.04 g) was obtained according to a similar manner to that of Example 12 from N-phenoxycarbonylamino-1,2,3,6-tetrahydropyridine (1.53 g) and 4-hydroxyaniline (1.09 g).

mp: 185.5―187°C.
IR (Nujol): 3190, 1660 cm-'.

NMR (CD₃OD, δ): 2.10-2.58 (2H, m), 2.93 (2H, t, J=5.5Hz), 3.20-3.52 (2H, m), 5.59-5.86 (2H, m), 6.70 (2H, d, J=8Hz), 7.20 (2H, d, J=8Hz).

Example 21

N-[[(4-Methoxycarbonylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.25 g) was obtained according to a similar manner to that of Example 12 from N-phenoxycarbonylamino-1,2,3,6-tetrahydropyridine (1.53 g) and methyl 4-aminobenzoate (1.51 g).

mp: 182.5―183°C.
IR (Nujol): 1715, 1680 cm^-1.

NMR (CDCI₃, δ): 2.16-2.63 (2H, m), 2.76-3.23 (2H, m), 3.26-3.74 (2H, m), 3.87 (3H, s), 5.53-5.98 (2H, m), 6.04 (1H, s), 7.58 (2H, d, J=6Hz), 8.02 (2H, d, J=6Hz), 8.44 (1H, s).

Example 22

(1) N-[[(4-Fluorophenyl)carbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine
- mp: 200.5―212°C.
- IR (Nujol): 3340, 3160, 3070, 1670, 1540 cm^-1.
(2) N-[[(3-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 136.5―138.5°C.
- IR (Nujol): 3280, 3200, 3100, 1685 cm^-1.
(3) N-[[(4-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 165.5―167.5°C.
- IR (Nujol): 3330, 3170, 3100, 1685 cm^-1.
(4) N-[[(3-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 145.5―147°C.
- IR (Nujol): 3340, 3190, 3090, 1680 cm^-1.
(5) N-[(p-Tolylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 179-180°C.
- IR (Nujol): 3350, 3170, 3050, 1675 cm^-1. 14
(6) N-[[(4-Trifluoromethylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 159.5―161°C.
- IR (Nujol): 3340, 3200, 3100, 1690 cm^-1.
(7) N-[(1-Naphthylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 181.5―183.5°C.
- IR (Nujol): 3350, 3175, 3075, 1675 cm^-1.
(8) N-(Phenylcarbamoylamino)-1,2,3,6-tetrahydropyridine
- mp: 157-159°C.
- IR (Nujol): 3340, 3190, 3100, 1680 cm-'.
(9) N-[[(2-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 119-121°C.
- IR (Nujol): 3360, 3200, 3100, 1690, 1620, 1600 cm^-1.
(10) N-[[(4-Dimethylaminophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 179.5―180°C.
- IR (Nujol): 1680 cm-'.
(11) N-[[(4-Acetylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 142.5―143°C.
- IR (Nujol): 1685, 1670 cm^-1.
(12) N-[[(2,4-Difluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 136.5―137°C.
- IR (Nujol): 1695 cm^-1.
(13) N-[[(4-Carboxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: >240°C.
- IR (Nujol): 1700 cm^-1.
(14) N-[[(4-Fluorophenyl)thiocarbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 163-164.5°C.
- IR (Nujol): 3260, 2930, 1540, 1505, 1460 cm^-1.
(15) N-[[(4-Fluorophenyl)thiocarbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine
- mp: 192.5-194.5⁰C.
- IR (Nujol): 3300, 3125, 1540, 1510 cm^-1.

Example 23

To a solution of N-(phenylcarbamoylimino)pyridinium ylide (0.64 g) in a mixture of ethanol (30 ml) and water (10 ml) was added sodium borohydride (0.20 g) at ambient temperature. After being stirred for 4 hours, the reaction mixture was acidified with 1 N hydrochloric acid, concentrated to a volume of ca. 15 ml. The crystalline precipitate was collected, washed with water and dried in vacuo. The crude product was dissolved in ethyl acetate and extracted with 10% hydrochloric acid (20 ml). The extract was adjusted to pH 3 with aqueous sodium bicarbonate and extracted with ethyl acetate (30 ml). The organic layer was washed with aqueous sodium bicarbonate (10 ml), dried over magnesium sulfate and evaporated to give N-(phenylcarbamoylamino)-1,2,3,6-tetrahydropyridine (0.28 g), which was recrystallized from ethyl acetate to afford colorless needles (0.15 g).

mp: 157-159°C.
IR (Nujol): 3340, 3190, 3100, 1680 cm^-1.
NMR (CD₃OD, δ): 2.36 (2H, m), 2.96 (2H, t, J=5.5Hz), 5.73 (2H, m), 7.0-7.6 (5H, m).

Example 24

A suspension of N-[[(4-fluorophenyl)carbamoyl]imino]pyridinium ylide (1.04 g) and sodium borohydride (2.55 g) in ethanol (100 ml) was stirred at ambient temperature for 16 hours. Excess of sodium borohydride was decomposed with water, and the resulting mixture was evaporated. The residue was extracted with chloroform (20 ml x 3). The combined organic extract was washed with water, dried over magnesium sulfate and evaporated to give crystals. Recrystallization from diisopropyl ether gave N-[[(4-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (0.60 g).

mp: 156-157°C.
IR (Nujol): 3340, 3200, 3100, 1680, 1605 cm^-1.
NMR (CDCI₃, 6): 2.31 (2H, m), 2.92 (2H, t, J=7Hz), 5.78 (2H, m), 6.87-7.48 (4H, m).

Example 25

The following compounds are obtained according to a similar manner to that of Example 23.

(1) N-[[(4-Fluorophenyl)carbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine
- mp: 200.5-212°C.
- IR (Nujol): 3340, 3160, 3070, 1670, 1540 cm^-1.
(2) N-[[(3-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 136.5-138.5°C.
- IR (Nujol): 3280, 3200, 3100, 1685 cm^-1.
(3) N-[[(4-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 165.5-167.5°C.
- IR (Nujol): 3330, 3170, 3100, 1685 cm^-1.
(4) N-[[(3-Chlorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 145.5-147°C.
- IR (Nujol): 3340, 3190, 3090, 1680 cm^-1.
(5) N-[(p-Tolylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 179-180°C.
- IR (Nujol): 3350, 3170, 3050, 1675 cm^-1.
(6) N-[[(4-Trifluoromethylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 159.5―161°C.
- IR (Nujol): 3340, 3200, 3100, 1690 cm^-1.
(7) N-[(1-Naphthylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 181.5-183.5°C.
- IR (Nujol): 3350, 3175, 3075, 1675 cm-'.
(8) N-[[(2-Fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 119―121°C.
- IR (Nujol): 3360, 3200, 3100, 1690, 1620, 1600 cm^-1.
(9) N-[[(4-Dimethylaminophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 179.5-180°C.
- IR (Nujol): 1680 cm-'.
(10) N-[[(2,4-Difluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 136.5―137°C.
- IR (Nujol): 1695 cm^-1.
(11) N-[(N-Methyl-N-phenylcarbamoyl)amino]-1,2,3,6-tetrahydropyridine
- mp: 99-99.5°C.
- IR (Nujol): 3250, 2950, 2870, 1645 cm^-1.
(12) N-[[(4-Hydroxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 185.5-187°C.
- IR (Nujol): 3190, 1660 cm-'.
(13) N-[[(4-Methoxycarbonylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 182.5-183°C.
- IR (Nujol): 1715, 1680 cm-'.
(14) N-[[(4-Carboxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: >240°C.
- IR (Nujol): 1700 cm-'.
(15) N-[[(4-Fluorophenyl)thiocarbamoyl]amino]-1,2,3,6-tetrahydropyridine
- mp: 163-164.5°C.
- IR (Nujol): 3260, 2930, 1540,1505, 1460 cm^-1.
(16) N-[[(4-Fluorophenyl)thiocarbamoyl]amino]-4-phenyl-1,2,3,6-tetrahydropyridine
- mp: 192.5-194.5°C.
- IR (Nujol): 3300, 3125, 1540, 1510 cm^-1.

Example 26

To a solution of N-[[(4-methoxycarbonylphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (1.21 g) in a mixture of methanol (30 ml) and chloroform (30 ml) was added. 1 N sodium hydroxide (10 ml) and the mixture was stirred at ambient temperature for 18 hours. After evaporation of the solvent, the residue was extracted with chloroform (20 ml x 3). The extract was washed with water, dried over magnesium sulfate and concentrated in vacuo. The residue was purified by column chromatography on silica gel (40 g) eluting with chloroform, to give N-[[(4-carboxyphenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine (0.65 g).

mp: >240°C.
IR (Nujol): 1700 cm-¹.

NMR (D₂0 + NaOD, δ): 2.12-2.49 (2H, m), 2.94 (2H, t, J=5Hz), 3.16-3.44 (2H, m), 5.68-6.01 (2H, m), 7.41 (2H, d, J=8Hz), 7.87 (2H, d, J=8Hz).

Claims

1. A compound of the formula:

wherein

R¹ is hydrogen,

R²and R³ are taken together with the adjacent nitrogen atom to form tetrahydropyridyl optionally substituted with phenyl,

R⁴ is naphthyl or phenyl which may have substituent(s) selected from C₁ to C₆ alkyl, halogen, C₁ to C₆ alkylamino, halo(C₁ to C₆)alkyl, hydroxy, C, to C₆ alkanoyl, C₁ to C₆ alkoxycarbonyl, phenoxycarbonyl, benzyloxycarbonyl and carboxy,

R⁵ is hydrogen or C₁ to C₆ alkyl, and

X is 0 or S, and pharmaceutically acceptable salts thereof.

2. A compound of claim 1, wherein

R¹ is hydrogen, and

R²and R³ are taken together with the adjacent nitrogen atom to form 1,2,3,6-tetrahydropyridin-1-yl optionally substituted with phenyl.

3. A compound of claim 2, wherein X is O.

4. A compound of claim 3, wherein R⁴ is phenyl optionally having substituent(s) selected from halogen and C₁ to C₆ alkylamino.

5. A compound of claim 4, which is N-(phenylcarbamoylamino)-1,2,3,6-tetrahydropyridine.

6. A compound of claim 4, which is N-[[(2-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine.

7. A compound of claim 4, which is N-[[(3-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine.

8. A compound of claim 4, which is N-[[(4-fluorophenyl)carbamoyl]amino]-1,2,3,6-tetrahydropyridine.

9. A process for preparing a compound of the formula:

wherein

R' is hydrogen,

R² and R³ are taken together with the adjacent nitrogen atom to form tetrahydropyridyl optionally substituted with phenyl,

R⁴ is naphthyl or phenyl which may have substituent(s) selected from C₁ to C₆ alkyl, halogen, C₁ to C₆ alkylamino, halo(C₁ to C₆)alkyl, hydroxy, lower alkanoyl, C₁ to C₆ alkoxycarbonyl, phenoxycarbonyl, benzyloxycarbonyl and carboxy,

R⁵ is hydrogen or C₁ to C₆ alkyl, and

X is 0 or S, and pharmaceutically acceptable salts thereof, which comprises,

a) reacting a compound of the formula:

or its salt with a compound of the formula:

or its salt to provide a compound of the formula:

or its pharmaceutically acceptable salt, in the above formulas, R¹, R², R³, R⁴ and X are each as defined above,

b) reacting a compound of the formula:

or its salt with a compound of the formula:

or its reactive derivative or a salt thereof to provide a compound of the formula:

or its pharmaceutically acceptable salt, in the above formulas, R¹, R², R³, R⁴, R⁵and X are each as defined above,

c) reacting a compound of the formula:

or its reactive derivative or a salt thereof with a compound of the formula:

or its salt to provide a compound of the formula:

or its pharmaceutically acceptable salt, in the above formulas, R¹, R², R³, R⁴, R⁵ and X are each as defined above,

d) reducing a compound of the formula:

or its salt to provide a compound of the formula:

or its pharmaceutically acceptable salt, in the above formulas, R², R³, R⁴, R⁵ and X are each as defined above, and Y is hydrogen or phenyl, or

e) subjecting a compound of the formula:

or its salt to de-esterification reaction to provide a compound of the formula:

or its pharmaceutically acceptable salt, in the above formulas, R', R², R³, R⁵and X are each as defined above,

is naphthyl or phenyl substituted with C₁ to C₆ alkoxycarbonyl, phenoxycarbonyl or benzyloxycarbonyl, and

is naphthyl or phenyl substituted with carboxy.

10. A pharmaceutical composition comprising a compound of claim 1, as an effective ingredient, in association with a pharmaceutically acceptable, substantially nontoxic carrier or excipient.

11. A pharmaceutical composition for treatment of inflammation or various pains of human beings or animals, which comprises a compound of claim 1.

12. Compounds of claim 1 for use as a medicament.